AES New York 2017
Engineering Brief EB05
EB05 - Posters—Part 2
Saturday, October 21, 9:00 am — 10:30 am (Poster Area)
EB05-1 Impulse and Radiation Field Measurements for Single Exciter versus Exciter Array Flat-Panel Loudspeakers—David Anderson, University of Rochester - Rochester, NY, USA; Michael Heilemann, University of Rochester - Rochester, NY, USA; Mark F. Bocko, University of Rochester - Rochester, NY, USA
Flat-panel loudspeakers with single exciters exhibit significant directivity shifts and many discrete resonances in frequency regions of low modal density. These phenomena are demonstrated through mechanical and acoustic measurements on an acrylic and a glass prototype panel, both with single exciters. The measurements are repeated for the acrylic panel using an array of exciters where the force magnitude of each exciter is specified to actuate only the lowest-index bending mode. The mechanical measurements demonstrate that no modes in the array-addressable frequency region above the first mode are actuated. Acoustically, measurements show omnidirectional radiation with a single low-frequency resonance, showing how the exciter array enables the flat panel to behave similarly to a conventional loudspeaker within the array-addressable frequency region.
Engineering Brief 379 (Download now)
EB05-2 Implementation of a Dipole Constant Directivity Circular-Arc Array—Kurtis Manke, Thompson Rivers University - Kamloops, BC, Canada; Richard Taylor, Thompson Rivers University - Kamloops, BC, Canada; Mark Paetkau, Thompson Rivers University - Kamloops, Canada; D. B. (Don) Keele, Jr., DBK Associates and Labs - Bloomington, IN, USA
We briefly present the theory for a broadband constant-beamwidth transducer (CBT) formed by a conformal circular-arc array of dipole elements previously developed in seminal works. This technical report considers a dipole CBT prototype with cosine amplitude shading of the source distribution. We show that this leads to a readily-equalizable response from about 100 Hz to 10 kHz with a far-field radiation pattern that remains constant above the cutoff frequency determined by the beam-width and arc radius of the array, and below the critical frequency determined by discrete element spacing at which spatial aliasing effects occur. Furthermore, we show that the shape of the radiation pattern is the same as the shading function, and remains constant over a broad band of frequencies.
Engineering Brief 381 (Download now)
EB05-3 Flexible Control of the Transducer and the Duct Resonance of a Speaker System Ducted to the Exterior of a Vehicle Cabin—Takashi Kinoshita, Bose Automotive G.K. - Tokyo, Tokyo, Japan; John Feng, Bose - Framingham, MA, USA
In order to reproduce lower frequency sound in a vehicle cabin efficiently, Zeljko Velican proposed a speaker system, where the backside of a transducer unit communicates with the exterior of a vehicle cabin via a tuned acoustic appliance.  Since this speaker system couples the interior and the exterior of a vehicle cabin, the efficiency and the frequency range of internal and external noise transmission are both important considerations. These two characteristics are strongly correlated with the two dominant resonances of the system. One is the mechanical resonance of the transducer which defines the lower limit of the sound reproduction frequency range. Another one is the Helmholtz resonance of the back-side acoustic appliance (enclosure and duct), which defines the frequency where, for example, noise transmission through the appliance is optimized. Choosing the appropriate acoustic parameters to balance those two dominant resonances is the key to optimal design this speaker system. But with the existing configuration , these two dominant acoustic resonances have strong mutual interaction via coupled design parameters, it can be difficult to find a good compromise between them. In this paper, a new speaker system configuration, consists of a transducer, an enclosure ducted to the exterior of the vehicle cabin, and a passive radiator to cover the duct, will be proposed and discussed. With this configuration, the two dominant resonances of the system can be controlled quasi-individually, therefore enhancing design flexibility for the practical use of such systems on a vehicle.
Engineering Brief 383 (Download now)
EB05-4 Multichannel Microphone Array Recording for Popular Music Production in Virtual Reality—Hashim Riaz, University of York - York, Yorkshire, UK; Mirek Stiles, Abbey Road Studios - London, UK; Cal Armstrong, University of York - York, UK; Andrew Chadwick, University of York - York, UK; Hyunkook Lee, University of Huddersfield - Huddersfield, UK; Gavin Kearney, University of York - York, UK
There is a growing market for innovative ways to appreciate and listen to music through new Virtual Reality (VR) experiences made accessible through smartphones and VR headsets. However, production workflows for creating immersive musical experiences over VR are still in their infancy. This engineering report documents different microphone configurations and recording techniques applied in a higher-order Ambisonic processing framework to deliver an engaging and hyper-real interactive VR music experience. The report documents a live popular music recording undertaken at Abbey Road with traditional music recording techniques such as spot and stereo microphone setups and advanced techniques using dedicated VR multichannel microphone arrays.
Engineering Brief 384 (Download now)
Engineering Brief 385 (Download now)
EB05-6 Consonant Perception and Improved S/N Ratio Using Harmonic Tracking Equalization—Al Yonovitz, University of Montana - Missula, MT, USA; Silas Smith, University of Montana - Missula, MT, USA; David Yonovitz, Key 49 - Del Mar, CA, USA
Audio equalization techniques are often used to enhance signals and reduce noise. These include Shelf, Parametric, and Graphic Equalizers. These techniques modify spectral components within specified bands by applying gain or attenuation. Another promising technique utilizes the tracking of harmonics and sub-harmonics (HTEq). These harmonics may be individually changed in intensity. This study utilized 21 Consonant Vowel (CV) stimuli with a white noise masker (+6 dB S/N). Each stimulus was randomly presented to listeners. Confusion matrices determined consonant intelligibility and information transmission for distinctive features. Perceptually, after HTEq, the noise was minimally audible and required considerably less effort to identify consonants. The results indicated the distinctive feature transmission was not altered. Comparisons were made for consonants at various levels of noise reduction.
Engineering Brief 386 (Download now)
EB05-7 Bridging Fan Communities and Facilitating Access to Music Archives through Semantic Audio Applications—Thomas Wilmering, Queen Mary University of London - London, UK; Centre for Digital Music (C4DM); Florian Thalmann, Queen Mary University of London - London, UK; György Fazekas, Queen Mary University of London - London, UK; Mark Sandler, Queen Mary University of London - London, UK
Semantic Audio is an emerging field in the intersection of signal processing, machine learning, knowledge representation, and ontologies unifying techniques involving audio analysis and the Semantic Web. These mechanisms enable the creation of new applications and user experiences for music communities. We present a case study focusing on what Semantic Audio can offer to a particular fan base, that of the Grateful Dead, characterized by a profoundly strong affinity with technology and the internet. We discuss an application that combines information drawn from existing platforms and results from the automatic analysis of audio content to infer higher-level musical information, providing novel user experiences particularly in the context of live music events.
Engineering Brief 387 (Download now)
EB05-8 The ANU School of Music Recording Studios: Design, Technology, Research, and Pedagogy—Samantha Bennett, Australian National University - Canberra, ACT, Australia; Matt Barnes, Australian National University - Canberra, Australia
This engineering brief addresses the refurbishment process of the School of Music, Australian National University recording studios to include focus on the historical, pedagogical and research requirements of a 21st Century studio facility. The brief will first address issues of space, heritage and purpose before considering the acoustic (re)design process. Furthermore, the brief examines issues of technological integration and facilitation of analogue, digital and hybrid workflows. Finally, the brief considers the research and pedagogical remit of the refurbished facilities.
Engineering Brief 397 (Download now)